Basic Java Knowledge

One: Common DOS commands

C:/user/xxxx D: Toggle Drive Letter

Dir : Displays all files and folders in the current folder.

CD path : Enter to the specified path.

Cd.. : go back to the top level directory

CD \: back to the current directory with the directory

MD folder name create a folder

Rd Folder name Delete Folder Action

echo data ( content ) > file name Create a file and specify the data.

Type file name to view the contents of the specified file

del file name deletes the specified file

* wildcard characters

tab Fill Content

CLS Clear Screen

Up and down ARROW keys Get back what you wrote last time

Exit Close the console.

Second: The construction of the Java environment

Jre:java the operating environment. Jre = java virtual machine + Core class library ( files that are run by Auxiliary java ) ;

Jdk:java development tool set jdk = JRE + java Development tools

description of the JDK directory:

Development tools for Bin:java

Db:jdk7 comes with a miniature database Derby

Include : The file that holds the calling system interface

Jre : java Runtime Environment

Lib : Core class Library

source code for Src.zip:java

Development tools for Java

Javac.exe:java compiler to compile the source file into a . class file

Java.exe : The java file is running

Path environment variable

How to configure path :

My Computer --- "right -- "Properties --- Advanced system settings --- -- -- " path---> edit ( Double-click )

Locate The file directory where the Java development tools are located, copy the directory, paste it to The back of the path, and give it a semicolon after the win7 is finished pasting. ( english )-----------[ If I'm d:/Javac, the system will find a Javac in the current folder .] executable file, it will not be configured by default . Path find the path in the environment if you find it, run it, no, it's not an internal instruction. ]

Three: Annotations in Java

1. single-line comment: //

2. Multiline Comment :/* contents of comment * /

3. Documentation Comments:/** comments * /

Note the details that need attention:

A multiline comment cannot be nested, and a single-line comment can be used in a nested set.

The role of annotations:

1. Explanation Procedure

2. Debug the program.

Basic Java Knowledge